The primary objectives of this research project are the design, development, and evaluation of an improved ultrasound imaging system for diagnostic use. This new imaging system will utilize a multi-element transducer array which will be electronically phased in both the transmission and reception modes. The ultrasound beam will thus be electronically scanned through the subject providing a very high data acquisition rate and, in turn, the possibility of dynamic imaging of non-stationary targets. Specifically, image frame rates of from 20 to 40 frames per second will be produced for imaging dynamic cardiovascular structures. In addition to the primary advantage of very high speed on-line imaging of dynamic structures, this system will have the feature of contact scanning eliminating the need for a water bath coupling media. This contact scanning will be entirely electronic and will require no mechanical motion of the transducer and no electro-mechanical transducer position sensing mechanisms.